Product Briefing Outline: K-Patents launched the Semicon Process Refractometer PR-23-MS real-time chemical concentration monitoring system. PR-23-MS provides a continuous 4-20 mA or digital measurement signal, which offers many possibilities for real-time monitoring and process control. It is physically small and easy to install in the bulk chemicals supply and distribution, and in point-of-use chemical blending, mixing, dilution and spiking applications. 

Problem: Low and high concentration alarms can be configured to prevent wrong liquids reaching the fabrication process and thus costly production problems and equipment damage can be avoided. The rationale is that changes in chemical quality can occur during in-house handling and storage. Factors such as human error in container handling and equipment failure at the distribution point are now also taken into account.

Solution: The PR-23-MS technology also assists in various wet etch, wafer cleaning and planarization operations where it helps to increase the number of wafers pass-in, saves chemical consumption and improves environmental performance of chemicals waste management. The company claims that typical polymer removal chemical savings in post-etch wafer cleaning can be up to 20 percent and the increase in wafers pass-in up to 40 percent. The PR-23-MS is mounted directly in-line. The workers need not tap off lab samples and analyze hazardous chemicals in the laboratory.

Applications: Typical monitored liquids are KOH (Potassium hydroxide), H₂SO₄ (Sulphuric acid), HF (Hydrofluoric acid), NH₄OH (Ammonium hydroxide), HCl (Hydrochloric acid), IPA (Isopropyl alcohol), Ethylene glycol, Acetone and others. Chemical mixtures, for example STD-1, SC-2, RCA-1, RCA-2, SPM, DHF, etc., are also measured.

Platform: PR-23-MS has a built-in flow cell designed to keep all metal and corroding parts from coming into contact with the process liquid. All the wetted parts are made of non-metallic materials, either PTFE or PFA (Teflon) or PVDF (Kynar). The prism material is spinel or sapphire.

Availability: July 2007 onwards.

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